Structure, Biosynthesis, and Function of Queuosine in Transfer RNA

The chapter discusses the structure, biosynthesis, and function of queuosine in transfer RNA. This chapter is concerned with the chemistry and biochemistry of queuosine— that is, with the isolation, structural characterization, location, and biosynthesis, and is thus quite straight forward. The chapter discusses biosynthesis of queuosine in tRNA, such as in vivo experiments, tRNA-guanine transglycosylase, and biosynthesis of queuosine in the tRNA's of animal cells. The biosynthesis of queuosine as well as of isopentenyl adenosine in the anticodon proceeded only after the removal of the intervening sequence, although the precursor tRNA already contained five other modifications. The chapter discusses the presence of queuine-lacking tRNA in tumor cells. The chapter also deals with the function of queuosine. Since no final conclusion on the function of queuosine can be drawn, the chapter summarizes all the results so far obtained, even though contradictory in some cases, and mention some ongoing experiments, hoping that ideas for future investigations and/or approaches may eventuate.